Priming mixture for small-arms ammunition



Patented Dec. 11, 1928.

UNITED STATES 1,694,890 PATENT OFFICE.

HARLEY T. PECK, OF LEBANON, OHIO, ASSIGNOR TO THE PETERS CARTRIDGE COM- PANY, OF CINCINNATI, OHIO, A CORPORATION OF, OHIO. I

PRIMING- MIXTURE FOR SMALL-ARMS AMMUNITION.

No Drawing.

This invention has for its object the provision of primers for small arms ammunition which shall be of improved composition and efficiency.

The invention is exemplified in the composition of material described in the following specification, and it is more particularly pointed out in the appended claims.

Particularly my improved priming mixture possesses the valuable property of leaving no corrosive or rust forming residue within the barrel or bore of the fire arm.

In a rim fire primer the priming mixture iscontained in the head of the cartridge case within the annular rim or cavity provided for this purpose. It is held in place by gum, collodion or some suitable adhesive.

In a center fire primer the priming mixture is contained in a metal cup inserted into the head of the cartridge case.

My invention relates to the use of an improved compositionof matter consisting of mercury fulminate, an alkali or alkali-earth chromate such as potassium, calcium, or barium chromate, or a heavy metal chromate such as leadchromate in combination with one or more suitable fuel agents such as lead sulphocyanate or antimony sulphide or pentaerythrite-tetranitrate (hereafter designated as PETN) and with a second oxidizing agent which is chosen for its property of leaving a rust resisting residue. Such an oxidizing agent is barium nitrate.

In the past, potassium chlorate has been used generally as an oxidizing agent in priming mixtures. Potassium chlorate leaves after burning a residue of chlorides which in conjunction with moisture under ordinary atmospheric conditions induces rust to form quickly within the barrel of the rifle if not cleaned and oiled properly. In my invention the potassium chlorate is eliminated and other valuable and rust resisting oxidizing agents are used in its place. a The most important ingredient in my improved rustless priming mixture is embodied in the chromate or chromates employed therein as oxidizing agents. In-the absence of potassium chlorate great difliculty was encountered in the selection of oxidizing agents which would combine with the other ingredients of the priming mixture to produce the desired degree of sensitiveness under the firing pin blow, the correct amount of heat and proper ignition of the propellant powders Application filed June 27, 1927. Serial No. 201,976.

so as to produce a finished cartridge which would function in all respects,'and especially with respect to accuracy and uniformity of velocity to the desired degree of excellence.

.I discovered that the alkali and alkali-earth chromates and the heavy metal chromates were suitable in this respect and in combination with the mercury fulminate andsuitable fuel ingredients produced a primer which after burning left not only the necessary rustless residues but also possessed the other val uable properties referred to above which are necessary in eflicient priming compositions.

An example of a priming composition suitable for rim fire cartridges is as follows:

40% Fulminate mercury.

24% Powdered glass.

8% Lead sulphocyanate; 2% PETN. 18% Barium nitrate (or another alkali or alkali-earth nitrate). 8% Lead chromate (or another heavy metal chromate).

Another example of my improved priming mixture would consist of:

38% Mercury fulminate.

24% Powdered glass.

10% Lead sulphocyanate.

18% Barium nitrate (or another alkali or alkali-earth nitrate).

10% Lead chromate (or another heavy *inetal chromate).

In all the above examples the various chromate salts employed are desirable not only for the production of the proper degree of sensitiveness to a firing pin blow but also to leave within the bore of the rifle, after the cartridge is fired, oxides and carbonates or other chemicalresidues which by their protective action resist rust and prevent the formation of rust within the bore of the rifle or other fire-arm. Barium nitrate although a may or may not be necessary to use powdered glass. As an example of my center fire rustless composition I submit the following:

30% Mercury fulminate.

34% Barium nitrate.

10% PETN.

10% Lead sulphocyanate.

Barium chromate.

10% Lead chromate.

It will be understood that, although the ingredients and proportions given herein define the best embodiments of my invention of-Which I am now aware, these ingredients and proportions may be 'varied without destroying the beneficial results of the invention and without departing from the spirit and scope thereof.

1. A priming mixture containing mercury 2. A priming mixture containing mercury fulminate, barium nitrate, lead chromate, and a fuel agent.

3. A priming mixture containing approximately 40% mercury fulminate, 24% powdered glass, 8% lead sulphocyanate, 2% penlaerythrite-tetranitrate, 18% alkali or alkalicarth nitrate, 8% heavy metal chromate.

4. A priming mixture comprising approximately 30% mercury fulminate, 34% barium nitrate, 10% pentaerythrite-tetranitrate,10% lead sulphocyanate, 6% barium chromate, 10% lead chromate.

In testimony whereof I have signed my name to this specification on this 20th day of June, A. D. 1927.

HARLEY T. PECK. 

